Doctoral Degrees (Civil Engineering)

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Browsing Doctoral Degrees (Civil Engineering) by Author "Cicione, Antonio"

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    Fire Dynamics in Informal Settlements
    (Stellenbosch : Stellenbosch University, 2019-12) Cicione, Antonio; Walls, Richard Shaun; Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.
    ENGLISH ABSTRACT: In poor and densely populated countries, the rapid growth in population leads to an increase in landlessness. As a result, the number of people residing in informal settlements is increasing on a daily basis. It is estimated that there are currently one billion people living in informal settlements and this number is expected to increase in the coming years. Currently, informal settlements are being ravaged by large fires every day across the globe. Over the past decades, fire related disasters have decreased in the global north, while they have increased in the global south. Since the number of people that reside in informal settlements are expected to increase, it is a cause for serious concern to see how little is done in terms of fire safety in these communities. It is with this in mind that this dissertation focusses on developing an in-depth understanding of fire dynamics in informal settlements, with the hope that it can form the basis for future research and fire safety innovations. In this dissertation four full-scale fire experiments have been carried out: (a) a single steel sheeting clad experiment, (b) a single timber plank clad experiment, (c) a triple dwelling steel sheeting clad experiment and (d) a triple dwelling timber plank clad experiment. The single dwelling experiments are analysed using two numerical models (i.e. two-zone modelling and Fire Dynamic Simulation (FDS) modelling) to obtain an understanding of the enclosure fire dynamics and heat fluxes emitted from these dwellings. A comparison between the model and experimental results are shown. The effect of different cladding materials (i.e. timber versus steel cladding) on the enclosure fire dynamics and heat fluxes experienced is also presented, where it was found that timber dwellings are more prone to fire spread, with heat fluxes exceeding 200 kW/m2 at the openings. It was found that the FDS models captured the behaviour of the single dwelling experimental fires well, but that the material properties of the cardboard lining have a substantial effect on how the fire develops, as a result of how the fire spreads across the surface of the cardboard. This was also the most difficult aspect to capture with the numerical models. The FDS models’ predictive capabilities were further utilised to determine a preliminary critical separation distance, where it was found to be approximately 3 m between dwellings (i.e. the distance needed for fire spread between dwellings not to occur under wind free conditions). The dissertation continues by presenting the results of the multi-dwelling experiments, where the basic understandings and findings drawn from the single dwelling experiments were used to examine the effect of different cladding materials on fire spread between dwellings. The multi-dwelling experimental results concurred that the timber dwellings are more prone to fire spread. These results highlighted the dangers of these closely spaced dwellings. For the timber clad dwellings, the overall spread time (i.e. from the start of flashover in the first dwelling to the end of flashover in the last dwelling) was approximately 4 minutes. Simplified FDS models are developed to predict fire spread between multiple dwellings, with the hope that these models can be improved over time so that they can be used to study housing configurations and fire spread interventions.